Optical Imaging System for Pickup

ABSTRACT

An optical imaging system for pickup, sequentially arranged from an object side to an image side, comprising: the first lens element with positive refractive power having a convex object-side surface, the second lens element with refractive power, the third lens element with refractive power, the fourth lens element with refractive power, the fifth lens element with refractive power; the sixth lens element made of plastic, the sixth lens with refractive power having a concave image-side surface with both being aspheric, and the image-side surface having at least one inflection point. By such arrangements, the optical imaging system for pickup satisfies conditions related to shorten the total length and to reduce the sensitivity for using in compact cameras and mobile phones with camera functionalities.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical imaging system for pickup,and more particularly to the optical imaging system for pickup comprisedof six lens elements to shorten total length and improve image qualityfor applying to electronic products.

2. Description of the Related Art

In compact electronic products such as digital still cameras, or mobilephone cameras, an optical imaging system for pickup is generallyinstalled for capturing images of an object, and the optical imagingsystem for pickup tends to be developed with a compact design and a lowcost, while meeting the user requirements for good aberration correctionability, high resolution, and high image quality.

In general, a conventional optical imaging system for pickup of acompact electronic product comes with different designs, including thetwo-lens, three-lens, four-lens, five-lens and six-or-more lens designs.However, if the imaging quality is taken into consideration, the opticalimaging system for pickup with the four-lens, five-lens or six-lensdesigns has advantages on image aberration and modulation transferfunction (MTF) performance, wherein the six-lens design having a higherresolution than the four-lens, or five-lens designs is suitable forelectronic products requiring high quality and high pixels.

In various compact designs of the six-lens optical imaging system forpickup having a fixed focal length, prior arts adopt differentcombinations of positive and negative refractive powers as disclosed inU.S. Pat. Nos. 5,682,269 and 5,513,046 adopting for a group of stackedlenses. For example, the first lens element with negative refractivepower and the second lens element with positive refractive power areused for shortening the total length of an optical system as disclosedin U.S. Pat. No. 7,564,634.

In products such as compact digital cameras, web cameras, and mobilephone cameras, the optical imaging system for pickup requires a compactdesign, a short focal length, and a good aberration correction. Wherein,the six-lens optical imaging system for pickup having a fixed focallength generally adopts the sixth lens element with positive refractivepower to allow the increase of the view angle so as to reduce the totallength of the optical imaging system. As disclosed in U.S. Pat. Nos,7,701,649, 4,389,099, and 4,550,987, adopting the optical imagingsystems tend to have a good aberration correction, but the total lengthof the optical imaging system for pickup still fails to satisfy thespecifications for compact electronic devices. In addition, acombination of the fifth lens element with negative refractive power andthe sixth lens element with positive refractive power is adopted, andthe refractive power and the rear focal length of the optical imagingsystem for pickup are adjusted to avoid aberrations caused by excessivepositive refractive power as disclosed in U.S. Pat. No. 3,997,248. Theseconventional designs must increase the rear focal length of the opticalimaging system for pickup, so that the total length of the opticalimaging system cannot be reduced.

Therefore, the present invention provides a more practical design toshorten the optical imaging lens assembly adopts a combination ofrefractive powers of six lens elements, convex and concave opticalsurfaces. Wherein the fifth lens element and the sixth lens element havepositive refractive power and negative refractive power respectively,and this complementary combination with a telecentric effect isfavorable for reducing the rear focal length and the total length of theoptical imaging system for pickup effectively as well as furtherimproving the image quality and applying the optical imaging lensassembly to compact electronic products.

SUMMARY OF THE INVENTION

Therefore, it is a primary objective of the present invention to providean optical imaging system for pickup, sequentially arranged from anobject side to an image side, comprising: the first lens element, thesecond lens element, the third lens element, the fourth lens element,the fifth lens element and the sixth lens element, wherein, the firstlens element with positive refractive power has a convex object-sidesurface; the second lens element has refractive power; the third lenselement has refractive power; the fourth lens element has refractivepower; the fifth lens element has refractive power; the plastic sixthlens element with refractive power has a concave image-side surface,both object-side surface and image-side surface being aspheric, and theimage-side surface having at least one inflection point; and thefollowing relation is satisfied:

1.8<|f/f ₅ |+|f/f ₆|<3.5;   (1)

wherein, f is the focal length of the optical imaging system for pickup,f₅ is the focal length of the fifth lens element, and f₆ is the focallength of the sixth lens element.

Moreover, the present invention provides an optical imaging system forpickup, as described above, made of at least three plastic lens elementsand further comprising a stop and an image sensor at an image plane forimaging a photographed object, wherein the second lens element withnegative refractive power has a concave image-side surface; the fifthlens element has positive refractive power; the sixth lens element withnegative refractive power has a concave object-side surface; and theoptical imaging system for pickup satisfies one or more of the followingrelations in addition to the relation (1):

0.7<S _(D) /T _(D)<1.2;   (2)

0.2<(CT ₃ +CT ₄ +CT ₅)/f<0.4;   (3)

TTL/ImgH<2.1;   (4)

0<(R ₇ −R ₈)/(R ₇ +R ₈)<0.6;   (5)

0<(R ₃ +R ₄)/(R ₃ −R ₄)<1.5;   (6)

2.0<|f/f ₅ |+|f/f ₆|<3.2;   (7)

wherein, S_(D) is an axial distance between the stop and the image-sidesurface of the sixth lens element, T_(D) is an axial distance betweenthe object-side surface of the first lens element and the image-sidesurface of the sixth lens element, CT₃ is a central thickness of thethird lens element, CT₄ is a central thickness of the fourth lenselement, CT₅ is a central thickness of the fifth lens element, TTL is anaxial distance between the object-side surface of the first lens elementand the image plane, ImgH is half of the diagonal length of an effectivephotosensitive area of the image sensor, R₃ is a curvature radius of theobject-side surface of the second lens element, R₄ is a curvature radiusof the image-side surface of the second lens element, R₇ is a curvatureradius of the object-side surface of the fourth lens element, R₈ is acurvature radius of the image-side surface of the fourth lens element, fis a focal length of the optical imaging system for pickup, f₅ is afocal length of the fifth lens element, and f₆ is a focal length of thesixth lens element.

Moreover, the present invention provides an optical imaging system forpickup, as described above, wherein the second lens element withnegative refractive power has a concave image-side surface; the fifthlens element has positive refractive power; the sixth lens element withnegative refractive power has a concave object-side surface; and theoptical imaging system for pickup satisfies one or more of the followingrelations in addition to the relation (1):

0.1<Y _(C) /f<0.8;   (12)

0.2<R ₁₂ /f<1.2;   (13)

0.03<T ₁₂ /T ₂₃<0.3;   (14)

wherein, Y_(C) is a vertical distance between the outermost horizontalvertex of the image side surface of the sixth lens element and theoptical axis (as shown in FIG. 7), f is a focal length of the opticalimaging system for pickup, R₁₂ is a curvature radius of the image-sidesurface of the sixth lens element, T₁₂ is an axial distance between thefirst lens element and the second lens element, and T₂₃ is an axialdistance between the second lens element and the third lens element.

Moreover, the present invention provides an optical imaging system forpickup, as described above, further comprising an image sensor at animage plane for imaging an photographed object, wherein the second lenselement with negative refractive power has a concave image-side surface;the fourth lens element has a concave object-side surface and a conveximage-side surface; the fifth lens element has a concave object-sidesurface and a convex image-side surface; the sixth lens element withnegative refractive power has a concave object-side surface; and theoptical imaging system for pickup satisfies one or more of the followingrelations in addition to the relation (1):

1.0<f/f ₁<2.0;   (8)

25<v ₁-v ₂<40;   (9)

−0.2<(R ₁₁ +R ₁₂)/(R ₁₁ −R ₁₂)<0.9;   (10)

3.7 mm<TTL<6.5 mm;   (11)

TTL/ImgH<2.1;   (4)

wherein, f is a focal length of the optical imaging system for pickup,f₁ is a focal length of the first lens element, v₁ is the Abbe number ofthe first lens element, v₂ is the Abbe number of the second lenselement, R₁₁ is the curvature radius of the object-side surface of thesixth lens element, R₁₂ is the curvature radius of the image-sidesurface of the sixth lens element, TTL is an axial distance between theobject-side surface of the first lens element and the image plane, andImgH is half of the diagonal length of an effective photosensitive areaof the image sensor.

Another objective of the present invention is to provide an opticalimaging system for pickup, sequentially arranged from an object side toan image side, comprising: the first lens element, the second lenselement, the third lens element, the fourth lens element, the fifth lenselement and the sixth lens element, wherein the first lens element withpositive refractive power has a convex object-side surface; the secondlens element has refractive power; the third lens element has refractivepower; the fourth lens element has refractive power; the fifth lenselement has refractive power; the plastic sixth lens element withrefractive power has a concave image-side surface, both object-sidesurface and image-side surface being aspheric, and the image-sidesurface having at least one inflection point; and optical imaging systemfor pickup satisfies the following relations:

1.8<|f/f ₅ +|f/f ₆|<3.5;   (1)

0.1<Y _(C) /f<0.8;   (12)

wherein, f is the focal length of the optical imaging system for pickup,f₅ is the focal length of the fifth lens element, f₆ is the focal lengthof the sixth lens element, and Y_(C) is the vertical distance betweenthe outermost horizontal vertex of the image side surface of the sixthlens element and the optical axis.

Moreover, the present invention provides an optical imaging system forpickup, as described above, further comprising an image plane; whereinthe second lens element has a concave image-side surface; the fourthlens element has a concave object-side surface and a convex image-sidesurface; the fifth lens element has a concave object-side surface and aconvex image-side surface; the sixth lens element has a concaveobject-side surface; and the optical imaging system for pickup satisfiesone or more of the following relations in addition to the relations (1)and (12):

3.7 mm<TTL<6.5 mm;   (11)

wherein, TTL is an axial distance between the object-side surface of thefirst lens element and the image plane.

With the arrangement of the aforementioned first lens element, secondlens element, third lens element, fourth lens element, fifth lenselement and sixth lens element with an appropriate interval apart fromone another, the present invention can provide a good aberrationcorrection and an advantageous modulation transfer function (MTF) in agreater field of view.

In the optical imaging system for pickup of the present invention, thefirst lens element with positive refractive power provides most of therefractive power required to assist reducing the total length, and thesecond lens element with negative refractive power can correctaberrations produced by the lens element with positive refractive powereffectively and correct the Petzval sum of the system to make the imagesurface on the edge flatter. If the second lens element has a concaveimage-side surface, the intensity of negative refractive power of thesecond lens element can be adjusted appropriately according to thesurface shape to provide a good aberration correction effect to thesystem. In addition, the meniscus fourth lens element and fifth lenselement having a concave object-side surface and a convex image-sidesurface can assist the aberration correction. The curvature ratio at theperiphery of the image-side surface facilitates suppressing the angle ofprojecting the light onto the sensor to enhance the light sensitivity ofthe image sensor. With the complementary fifth lens element withpositive refractive power and sixth lens element with negativerefractive power, the telecentric effect can be achieved to facilitatereducing the rear focal length, so as to shorten the total length.

In the optical imaging system for pickup of the present invention, thearrangement of the stop produces a longer distance between the exitpupil of the optical imaging system for pickup and the image plane sothat the imaging light can be projected directly and then received bythe image sensor to avoid dark corners or achieve the telecentric effecton the image side. In general, the telecentric effect can improve thebrightness of the image plane and enhance the speed of receiving imagesby the CCD or CMOS image sensor.

In the optical imaging system for pickup of the present invention, thecombination of the first lens element with positive refractive power,the second lens element with negative refractive power and the thirdlens element with positive or negative refractive power, and the mutualcompensation of the fifth lens element with positive refractive powerand the sixth lens element with negative refractive power can reduce thetotal length of the optical imaging system for pickup effectively, sothat the image sensor can have a larger effective pixel range within thesame total length. In other words, a shorter optical imaging system forpickup can be designed with the same effective pixel range of the imagesensor.

If the sixth lens element has an inflection point, the inflection pointcan be used for guiding imaging light with an angle out from the edgesof the fifth lens element, such that the imaging light at the off-axisview angle is guided to the image sensor and received by the imagesensor. In addition, the optical imaging system for pickup includes atleast three lens elements made of plastic to facilitate the manufacturewith lower costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of an optical imaging system for pickup inaccordance with the first preferred embodiment of the present invention;

FIG. 1B is a schematic view of a series of aberration curves of thefirst preferred embodiment of the present invention;

FIG. 2A is a schematic view of an optical imaging system for pickup inaccordance with the second preferred embodiment of the presentinvention;

FIG. 2B is a schematic view of a series of aberration curves of thesecond preferred embodiment of the present invention;

FIG. 3A is a schematic view of an optical imaging system for pickup inaccordance with the third preferred embodiment of the present invention;

FIG. 3B is a schematic view of a series of aberration curves of thethird preferred embodiment of the present invention;

FIG. 4A is a schematic view of an optical imaging system for pickup inaccordance with the fourth preferred embodiment of the presentinvention;

FIG. 4B is a schematic view of a series of aberration curves of thefourth preferred embodiment of the present invention;

FIG. 5A is a schematic view of an optical imaging system for pickup inaccordance with the fifth preferred embodiment of the present invention;

FIG. 5B is a schematic view of a series of aberration curves of thefifth preferred embodiment of the present invention;

FIG. 6A is a schematic view of an optical imaging system for pickup inaccordance with the sixth preferred embodiment of the present invention;

FIG. 6B is a schematic view of a series of aberration curves of thesixth preferred embodiment of the present invention; and

FIG. 7 is a schematic view of Yc of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1A, an optical imaging system for pickup of thepresent invention, sequentially arranged from an object side to an imageside along an optical axis, comprises the first lens element 110, thesecond lens element 120, the third lens element 130, the fourth lenselement 140, the fifth lens element 150 and the sixth lens element 160,wherein the first lens element 110 with positive refractive power has aconvex object-side surface 111; the second lens element 120 hasrefractive power; the third lens element 130 has refractive power; thefourth lens element 140 has refractive power; the fifth lens element 150has refractive power; the plastic sixth lens element 160 with refractivepower has a concave image-side surface 162, and both object-side surface161 and image-side surface 162 being aspheric, and the image-sidesurface 162 having at least one inflection point. The optical imagingsystem for pickup further comprises a stop and an IR-filter 170. Morespecifically, the stop can be an aperture stop 100 being a middle stopbetween the first lens element 110 and the second lens element 120; theIR-filter 170 is between the sixth lens element 160 and the image plane180 and generally made of panel glass without affecting the focal lengthof the optical imaging system for pickup of the present invention. Theoptical imaging system for pickup further comprises an image sensor 190at an image plane 180 for imaging a photographed object. The asphericsurfaces of the first lens element 110, second lens element 120, thirdlens element 130, fourth lens element 140, fifth lens element 150 andsixth lens element 160 comply with the aspherical surface formula asgiven in Equation (15).

$\begin{matrix}{{X(Y)} = {\frac{\left( {Y^{2}/R} \right)}{1 + \sqrt{\left( {1 - {\left( {1 + K} \right)\left( {Y/R} \right)^{2}}} \right)}} + {\sum\limits_{i}{\left( A_{i} \right) \cdot \left( Y^{i} \right)}}}} & (15)\end{matrix}$

Wherein, X is the relative height from a point on the aspherical surfacewith a distance Y between the optical axis and a tangent plane at thetip of the optical axis of the aspherical surface;

Y is the distance between a point on the curve of the aspherical surfaceand the optical axis;

R is the curvature radius;

K is the conic coefficient; and A_(i) is the i^(th) level asphericalsurface coefficient.

In the imaging system for pickup of the present invention optical, thefirst lens element 110, second lens element 120, third lens element 130,fourth lens element 140 and fifth lens element 150 can have spherical oraspheric surfaces. If aspheric optical surfaces are adopted, then thecurvature radius of the optical surface can be used for changing therefractive power to reduce or eliminate aberrations, so as to decreasethe number of lens elements used in the optical imaging system forpickup and shorten the total length of the optical imaging lens assemblyeffectively. The lens elements can be made of glass or plastic. If glasslens elements are adopted, the refractive power of the optical imagingsystem for pickup can be distributed with higher flexibility. If theplastic lens elements are adopted, the production cost can be lowered.With the arrangement of the first lens element 110, second lens element120, third lens element 130, fourth lens element 140, fifth lens element150 and sixth lens element 160, the optical imaging system for pickupsatisfies the relation (1).

In the optical imaging system for pickup of the present invention, thepositive refractive power is mainly provided by the first lens element110 and the fifth lens element 150, such that if the relation (1) issatisfied, the ratios among the focal length f₅ of the fifth lenselement 150, the focal length f₆ of the sixth lens element 160 and thefocal length f of the optical imaging system for pickup can allocate therefractive power required by the fifth lens element 150 of the opticalimaging system for pickup to reduce the sensitivity of the system inmanufacturing tolerance and provide the required appropriate positiverefractive power. In the meantime, the refractive power of the sixthlens element 160 can be adjusted to be complementary with the refractivepower of the fifth lens element 150 to produce the telecentric effect,so as to facilitate reducing the rear focal length and the total lengthand achieve a compact optical imaging system for pickup.

If the ratio of the focal length f₁ of the first lens element 110 andthe focal length f of the optical imaging system for pickup is limitedaccording to the relation (8), the positive refractive power of thefirst lens element 110 can be adjusted appropriately to further adjustthe focal length and reduce the total length of the system. When therelation (13) is satisfied, the sixth lens element 160 has a concaveimage-side surface 162, such that the principal point is far away fromthe image plane 180 to facilitate reducing the total length of theoptical lens system.

If the relation (4) is satisfied, the total length of the opticalimaging system for pickup can be reduced effectively, such that a largereffective pixel range of the image sensor can be achieved with the sametotal length. Similarly, if the relation (2) is satisfied, the positionof the stop and the distance between the first lens element 110 and thesixth lens element 160 can be adjusted appropriately to shorten thelength of the optical imaging system for pickup. If the total length ofthe optical imaging system for pickup is limited according to therelation (11), the system can have an appropriate total length. If thetotal length is too short, the length of each lens element must bedesigned with a smaller thickness. As a result, the yield rate of themanufactured lens elements would be relatively low, and the level ofdifficulty for the assembling process becomes higher.

Furthermore, if the relation (3) is satisfied, the focal length f of theoptical imaging system for pickup can adjust the thickness of the thirdlens element 130, fourth lens element 140, and fifth lens element 150 tofacilitate shortening the total length of the optical imaging system forpickup and enhancing the yield rate in the manufacturing process. If theratio of the axial distance T₁₂ between the first lens element 110 andthe second lens element 120 to the axial distance T₂₃ between the secondlens element 120 and the third lens element 130 is limited according tothe relation (14), an appropriate refractive angle of the light passingthrough the first lens element 110 and the air gap into the third lenselement 130 can shorten the total length.

If the curvature radius R₁₁ of the object-side surface 161 and thecurvature radius R₁₂ of the image-side surface 162 of the sixth lenselement 160 are limited according to the relation (10), the variation ofthe surface shape of the sixth lens element 160 will be limited. Sucharrangement can assist the aberration correction of the system andfacilitate allocating the refractive power of the sixth lens element 160to compensate the positive refractive power of the fifth lens element150 to produce the telecentric effect. In addition, the fourth lenselement 140 has a convex image-side surface 142, such that if the ratioof the curvature radii of the object-side surface 141 and the image-sidesurface 142 is limited according to the relation (5), the refractivepower of the fourth lens element 140 can be adjusted appropriately tolower the sensitivity of the system in manufacturing tolerance, enhancethe yield rate and lower the production cost. The meniscus fourth lenselement 140 has a concave object-side surface 141 and a conveximage-side surface 142 to provide the aberration correction function.Similarly, if the relation (6) is satisfied, the change of the surfaceshape of the second lens element 120 is limited to achieve theaberration correction function of the second lens element 120 withnegative refractive power.

If the relation (9) is satisfied, the difference between the Abbe numberv₁ of the first lens element 110 and the Abbe number v₂ of the secondlens element 120 is limited within an appropriate range to effectivelycorrect the chromatic aberrations produced by the first lens element 110and the second lens element 120, so as to enhance the chromaticaberration correction of the second lens element 120. If the verticaldistance Y_(C) between the outermost horizontal vertex of the image sidesurface 162 of the sixth lens element 160 and the optical axis and thefocal length f of the optical imaging system for pickup is limitedaccording to the relation (12), the range of negative refractive powerof the sixth lens element 160 is relatively larger, so as to strengthenthe aberration correction at a position near the optical axis. The rearfocal length of the optical imaging system for pickup can be adjustedappropriately to facilitate the reduction of the total length of thesystem.

The optical imaging system for pickup of the present invention isdescribed by means of preferred embodiments with relevant drawings asfollows.

First Preferred Embodiment

With reference to FIGS. 1A and 1B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the first preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 170. More specifically, the stop canbe an aperture stop 100, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: the plastic first lens element 110 withpositive refractive power having a convex object-side surface 111, and aconvex image-side surface 112, and both object-side surface 111 andimage-side surface 112 being aspheric; an aperture stop 100; the plasticsecond lens element 120 with negative refractive power having a concaveobject-side surface 121 and a concave image-side surface 122, bothobject-side surface 121 and image-side surface 122 being aspheric; theplastic third lens element 130 with negative refractive power having aconcave object-side surface 131 and a concave image-side surface 132,and both object-side surface 131 and image-side surface 132 beingaspheric; the plastic fourth lens element 140 with positive refractivepower having a concave object-side surface 141, and a convex image-sidesurface 142, and both object-side surface 141 and image-side surface 142being aspheric; the plastic fifth lens element 150 with positiverefractive power having a concave object-side surface 151 and a conveximage-side surface 152, and both object-side surface 151 and image-sidesurface 152 being aspheric; the plastic sixth lens element 160 withnegative refractive power having a concave object-side surface 161 and aconcave image-side surface 162, and both object-side surface 161 andimage-side surface 162 being aspheric, and the image-side surface 162having at least one inflection point; the IR-filter 170 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 190 at an image plane 180. With thecombination of the six lens elements, the aperture stop 100 and theIR-filter 170, an image of the object can be photographed at the imagesensor 190.

TABLE 1 Optical data of this preferred embodiment f = 3.91 mm, Fno =2.80, HFOV = 35.5 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Lens 1  1.526630(ASP) 0.504 Plastic 1.535 56.3 2.53 2 −10.629800 (ASP) −0.004   3 Ape.Stop Plano 0.074 4 Lens 2  −8.657100 (ASP) 0.250 Plastic 1.634 23.8−6.14 5  7.147300 (ASP) 0.487 6 Lens 3  −7.331600 (ASP) 0.254 Plastic1.634 23.8 −11.28 7 290.992300 (ASP) 0.182 8 Lens 4  −2.631200 (ASP)0.499 Plastic 1.544 55.9 4.90 9  −1.413080 (ASP) 0.084 10 Lens 5 −2.543500 (ASP) 0.512 Plastic 1.544 55.9 3.41 11  −1.148580 (ASP) 0.25812 Lens 6  −2.701230 (ASP) 0.600 Plastic 1.535 56.3 −1.84 13  1.666300(ASP) 0.500 14 IR-filter Plano 0.210 Glass 1.517 64.2 — 15 Plano 0.38816 Image Plano — Note: Reference wavelength is 587.6 nm. ASP stands foraspherical surfaces.

The optical data of this preferred embodiment are listed in Table 1,wherein the object-side surface and the image-side surface of the firstlens element 110 to the sixth lens element 160 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 2 as follows:

TABLE 2 Aspheric coefficients of this preferred embodiment Surface # 1 24 5 6 7 k = −6.27005E+00 2.40641E+01 3.46380E+01 −2.88534E+01−1.00000E+00 −5.00000E+01 A4 = 2.22067E−01 −8.91882E−03 1.11985E−02−5.37315E−03 −3.07329E−01 −1.89409E−01 A6 = −2.08448E−01 4.56934E−024.37210E−02 6.53337E−02 −1.28671E−01 −4.07177E−02 A8 = 2.21344E−01−2.30625E−01 2.77223E−01 1.29841E−01 3.77004E−01 1.31926E−01 A10 =−1.83460E−01 4.05257E−01 −9.77124E−01 −3.51259E−01 −4.49629E−01−6.72614E−02 A12 = −1.77376E−03 −5.65290E−01 1.42246E+00 4.58371E−013.49487E−01 2.99300E−02 A14 = −2.07420E−02 3.20599E−01 −6.98996E−01−1.14116E−01 Surface # 8 9 10 11 12 13 k = 3.45410E+00 −6.84920E−019.45035E−01 −4.86064E+00 −4.38056E+00 −1.00945E+01 A4 = 5.69545E−021.13192E−02 8.60026E−03 −1.17314E−01 −1.05554E−02 −5.91758E−02 A6 =8.04410E−02 1.69639E−02 −5.77304E−03 1.53311E−01 −2.53017E−021.89675E−02 A8 = −2.04985E−01 9.48472E−03 −1.63354E−03 −1.37395E−011.24249E−02 −7.02892E−03 A10 = 2.92427E−01 4.45615E−03 3.46661E−036.89020E−02 −9.37668E−04 1.64788E−03 A12 = −1.80316E−01 −1.48374E−02−1.68168E−04 −2.21901E−04 A14 = 4.37798E−02 8.72278E−04 1.06644E−051.26521E−05

With reference to Table 1 and FIG. 1B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=3.91 (mm), an f-number Fno=2.80, and a halfof maximum view angle HFOV=35.5°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 3, andthe related symbols have been described above and thus will not bedescribed again.

TABLE 3 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 32.5 f/f₁ 1.54 (CT₃ + CT₄ + CT₅)/f 0.32|f/f₅| + |f/f₆| 3.28 T₁₂/T₂₃ 0.14 Y_(C)/f 0.33 R₁₂/f 0.43 S_(D)/T_(D)0.86 (R₃ + R₄)/(R₃ − R₄) 0.10 TTL [mm] 4.73 (R₇ − R₈)/(R₇ + R₈) 0.30TTL/ImgH 1.65 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) 0.24

According to the optical data as shown in Table 1 and the series ofaberration curves as shown in FIG. 1B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

Second Preferred Embodiment

With reference to FIGS. 2A and 2B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the second preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 270. More specifically, the stop canbe an aperture stop 200, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: the plastic first lens element 210 withpositive refractive power having a convex object-side surface 211, and aconvex image-side surface 212, and both object-side surface 211 andimage-side surface 212 being aspheric; an aperture stop 200; the plasticsecond lens element 220 with negative refractive power having a concaveobject-side surface 221 and a concave image-side surface 222, bothobject-side surface 221 and image-side surface 222 being aspheric; theplastic third lens element 230 with positive refractive power having aconvex object-side surface 231 and a concave image-side surface 232, andboth object-side surface 231 and image-side surface 232 being aspheric;the plastic fourth lens element 240 with positive refractive powerhaving a concave object-side surface 241, and a convex image-sidesurface 242, and both object-side surface 241 and image-side surface 242being aspheric; the plastic fifth lens element 250 with positiverefractive power having a concave object-side surface 251 and a conveximage-side surface 252, and both object-side surface 251 and image-sidesurface 252 being aspheric; the plastic sixth lens element 260 withnegative refractive power having a concave object-side surface 261 and aconcave image-side surface 262, and both object-side surface 261 andimage-side surface 262 being aspheric, and the image-side surface 262having at least one inflection point; an IR-filter 270 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 290 at an image plane 280. With thecombination of the six lens elements, the aperture stop 200 and theIR-filter 270, an image of the photographed object can be formed at theimage sensor 290.

TABLE 4 Optical data of this preferred embodiment f = 4.25 mm, Fno =2.80, HFOV = 33.5 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Lens 1  1.555490(ASP) 0.534 Plastic 1.535 56.3 2.64 2 −13.416800 (ASP) 0.011 3 Ape. StopPlano 0.120 4 Lens 2 −13.101200 (ASP) 0.328 Plastic 1.634 23.8 −4.22 5 3.395800 (ASP) 0.340 6 Lens 3  9.543600 (ASP) 0.270 Plastic 1.634 23.8147.70 7  10.510000 (ASP) 0.355 8 Lens 4  −2.747300 (ASP) 0.477 Plastic1.535 56.3 6.36 9  −1.610980 (ASP) 0.137 10 Lens 5  −5.000000 (ASP)0.452 Plastic 1.544 55.9 7.11 11  −2.249950 (ASP) 0.485 12 Lens 6 −2.894340 (ASP) 0.497 Plastic 1.535 56.3 −2.66 13  2.971890 (ASP) 0.50014 IR-filter Plano 0.210 Glass 1.517 64.2 — 15 Plano 0.253 16 ImagePlano — Note: Reference wavelength is 587.6 nm. ASP stands foraspherical surfaces.

The optical data of this preferred embodiment are listed in Table 4,wherein the object-side surface and the image-side surface of the firstlens element 210 to the sixth lens element 260 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 5 as follows:

TABLE 5 Aspheric coefficients of this preferred embodiment Surface # 1 24 5 6 7 k = −7.02693E+00 −5.00000E+01 −2.91242E+01 −1.89048E+01−1.00000E+00 5.00000E+01 A4 = 2.30451E−01 3.56828E−03 2.49453E−047.71823E−03 −2.61376E−01 −1.78309E−01 A6 = −2.01916E−01 5.74683E−027.51352E−02 1.23723E−01 −8.06167E−02 −4.52248E−02 A8 = 1.81867E−01−1.96817E−01 2.23108E−01 2.84497E−02 3.33982E−01 1.33075E−01 A10 =−8.98109E−02 3.85114E−01 −1.01205E+00 −2.93027E−01 −4.58406E−01−6.17353E−02 A12 = 3.61373E−03 −5.65291E−01 1.42246E+00 4.58370E−013.49487E−01 1.20681E−02 A14 = −2.07423E−02 3.20599E−01 −6.98996E−01−1.14116E−01 Surface # 8 9 10 11 12 13 k = 3.98373E+00 −7.40958E−016.36387E+00 −1.80338E+01 −7.65254E−01 −4.17313E+00 A4 = 5.12181E−022.16403E−02 −1.71915E−02 −1.36794E−01 −1.80359E−02 −7.94465E−02 A6 =8.13768E−02 7.39668E−03 −1.67151E−02 1.45449E−01 −2.58288E−022.22449E−02 A8 = −1.98653E−01 1.96704E−03 −3.88524E−03 −1.38071E−011.22577E−02 −7.07442E−03 A10 = 2.91284E−01 2.46722E−03 4.23256E−036.86861E−02 −7.25967E−04 1.59073E−03 A12 = −1.86516E−01 −1.48288E−02−1.23061E−04 −2.22167E−04 A14 = 4.60425E−02 1.03714E−03 −5.33604E−071.38597E−05

With reference to Table 4 and FIG. 2B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=4.25 (mm), an f-number Fno=2.80, and a halfof maximum view angle HFOV=33.5°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 6, andthe related symbols have been described above and thus will not bedescribed again.

TABLE 6 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 32.5 f/f₁ 1.61 (CT₃ + CT₄ + CT₅)/f 0.28|f/f₅| + |f/f₆| 2.19 T₁₂/T₂₃ 0.39 Y_(C)/f 0.27 R₁₂/f 0.70 S_(D)/T_(D)0.86 (R₃ + R₄)/(R₃ − R₄) 0.59 TTL [mm] 4.90 (R₇ − R₈)/(R₇ + R₈) 0.26TTL/ImgH 1.71 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) −0.01

According to the optical data as shown in Table 4 and the series ofaberration curves as shown in FIG. 2B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

Third Preferred Embodiment

With reference to FIGS. 3A and 3B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the third preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 370. More specifically, the stop canbe an aperture stop 300, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: an aperture stop 300; the plastic first lenselement 310 with positive refractive power having a convex object-sidesurface 311, and a concave image-side surface 312, and both object-sidesurface 311 and image-side surface 312 being aspheric; the plasticsecond lens element 320 with negative refractive power having a convexobject-side surface 321 and a concave image-side surface 322, bothobject-side surface 321 and image-side surface 322 being aspheric; theplastic third lens element 330 with negative refractive power having aconcave object-side surface 331 and a convex image-side surface 332, andboth object-side surface 331 and image-side surface 332 being aspheric;the plastic fourth lens element 340 with positive refractive powerhaving a concave object-side surface 341, and a convex image-sidesurface 342, and both object-side surface 341 and image-side surface 342being aspheric; the plastic fifth lens element 350 with positiverefractive power having a concave object-side surface 351 and a conveximage-side surface 352, and both object-side surface 351 and image-sidesurface 352 being aspheric; the plastic sixth lens element 360 withnegative refractive power having a convex object-side surface 361 and aconcave image-side surface 362, and both object-side surface 361 andimage-side surface 362 being aspheric, and the image-side surface 362having at least one inflection point; an IR-filter 370 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 390 at an image plane 380. With thecombination of the six lens elements, the aperture stop 300 and theIR-filter 370, an image of the photographed object can be formed at theimage sensor 390.

TABLE 7 Optical data of this preferred embodiment f = 3.88 mm, Fno =2.80, HFOV = 35.6 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Ape. Stop Plano−0.170   2 Lens 1  1.377280 (ASP) 0.442 Plastic 1.514 56.8 2.99 3 firstlens  11.904800 (ASP) 0.075 element 4 Lens 2  5.710200 (ASP) 0.263Plastic 1.650 21.4 −8.15 5  2.698110 (ASP) 0.413 6 Lens 3  −4.302500(ASP) 0.250 Plastic 1.634 23.8 −10.06 7 −13.523900 (ASP) 0.175 8 Lens 4 −7.200600 (ASP) 0.558 Plastic 1.544 55.9 4.91 9  −2.000790 (ASP) 0.18710 Lens 5  −1.670080 (ASP) 0.459 Plastic 1.544 55.9 4.20 11  −1.058030(ASP) 0.325 12 Lens 6  10.526300 (ASP) 0.426 Plastic 1.544 55.9 −2.43 13 1.159080 (ASP) 0.500 14 IR-filter Plano 0.210 Glass 1.517 64.2 — 15Plano 0.483 16 Image Plano — Note: Reference wavelength is 587.6 nm. ASPstands for aspherical surfaces.

The optical data of this preferred embodiment are listed in Table 7,wherein the object-side surface and the image-side surface of the firstlens element 310 to the sixth lens element 360 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 8 as follows:

TABLE 8 Aspheric coefficients of this preferred embodiment Surface # 2 34 5 6 7 k = −4.94896E+00 −1.00000E+00 −5.00000E+01 −1.00000E+00−1.00000E+00 −5.00000E+01 A4 = 2.55745E−01 −1.22879E−02 −1.79634E−02−3.14831E−02 −2.44690E−01 −1.59058E−01 A6 = −1.76052E−01 2.74904E−02−2.04448E−02 4.75050E−02 −1.45713E−01 −4.49185E−02 A8 = 2.57160E−01−1.00248E−01 2.79387E−01 3.31342E−02 3.63477E−01 1.03680E−01 A10 =−2.10505E−01 1.68326E−01 −1.10021E+00 −3.52832E−01 −6.95831E−01−6.75585E−02 A12 = 4.72163E−02 −5.62962E−01 1.41611E+00 4.54599E−013.50965E−01 6.79089E−02 A14 = −2.85768E−02 3.20589E−01 −6.99005E−01−1.14125E−01 Surface # 8 9 10 11 12 13 k = 1.46001E+01 −1.65555E−011.78066E−01 −4.23181E+00 −1.00000E+00 −5.12007E+00 A4 = −6.04096E−03−1.71136E−02 4.05510E−02 −1.07593E−01 −6.85611E−02 −7.41849E−02 A6 =3.13490E−02 1.15126E−02 1.22064E−02 1.48159E−01 −2.16414E−02 2.16565E−02A8 = −2.02431E−01 6.06939E−03 3.61760E−03 −1.38014E−01 1.25179E−02−7.19811E−03 A10 = 3.05316E−01 2.26058E−04 3.11689E−03 6.92804E−02−9.68113E−04 1.64156E−03 A12 = −1.77145E−01 −1.45030E−02 −1.56811E−04−2.15742E−04 A14 = 3.61509E−02 8.38648E−04 1.77748E−05 1.25630E−05

With reference to Table 7 and FIG. 3B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=3.88 (mm), an f-number Fno=2.80, and a halfof maximum view angle HFOV=35.6°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 9, andthe related symbols have been described above and thus will not bedescribed again.

TABLE 9 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 35.4 f/f₁ 1.30 (CT₃ + CT₄ + CT₅)/f 0.33|f/f₅| + |f/f₆| 2.52 T₁₂/T₂₃ 0.18 Y_(C)/f 0.35 R₁₂/f 0.30 S_(D)/T_(D)0.95 (R₃ + R₄)/(R₃ − R₄) 2.79 TTL [mm] 4.69 (R₇ − R₈)/(R₇ + R₈) 0.57TTL/ImgH 1.64 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) 1.25

According to the optical data as shown in Table 7 and the series ofaberration curves as shown in FIG. 3B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

Fourth Preferred Embodiment

With reference to FIGS. 4A and 4B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the fourth preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 470. More specifically, the stop canbe an aperture stop 400, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: the plastic first lens element 410 withpositive refractive power having a convex object-side surface 411, and aconcave image-side surface 412, and both object-side surface 411 andimage-side surface 412 being aspheric; an aperture stop 400; the plasticsecond lens element 420 with negative refractive power having a concaveobject-side surface 421 and a concave image-side surface 422, bothobject-side surface 421 and image-side surface 422 being aspheric; theplastic third lens element 430 with negative refractive power having aconcave object-side surface 431 and a concave image-side surface 432,and both object-side surface 431 and image-side surface 432 beingaspheric; the plastic fourth lens element 440 with positive refractivepower having a concave object-side surface 441, and a convex image-sidesurface 442, and both object-side surface 441 and image-side surface 442being aspheric; the plastic fifth lens element 450 with positiverefractive power having a convex object-side surface 451 and a conveximage-side surface 452, and both object-side surface 451 and image-sidesurface 452 being aspheric; the plastic sixth lens element 460 withnegative refractive power having a concave object-side surface 461 and aconcave image-side surface 462, and both object-side surface 461 andimage-side surface 462 being aspheric, and the image-side surface 462having at least one inflection point; an IR-filter 470 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 490 at an image plane 480. With thecombination of the six lens elements, the aperture stop 400 and theIR-filter 470, an image of the object to be photographed can be formedat the image sensor 490.

TABLE 10 Optical data of this preferred embodiment f = 4.22 mm, Fno =2.80, HFOV = 33.5 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Lens 1  1.413570(ASP) 0.565 Plastic 1.514 56.8 2.79 2  85.858700 (ASP) 0.024 3 Ape. StopPlano 0.051 4 Lens 2 −36.468000 (ASP) 0.250 Plastic 1.650 21.4 −7.66 5 5.781700 (ASP) 0.500 6 Lens 3 −17.860200 (ASP) 0.281 Plastic 1.634 23.8−9.19 7  8.693400 (ASP) 0.150 8 Lens 4  −2.636290 (ASP) 0.447 Plastic1.535 56.3 9.53 9  −1.840020 (ASP) 0.220 10 Lens 5 500.000000 (ASP)0.414 Plastic 1.607 26.6 5.79 11  −3.541500 (ASP) 0.631 12 Lens 6 −3.123500 (ASP) 0.350 Plastic 1.535 56.3 −3.06 13  3.577900 (ASP) 0.40014 IR-filter Plano 0.210 Glass 1.517 64.2 — 15 Plano 0.323 16 ImagePlano — Note: Reference wavelength is 587.6 nm. ASP stands foraspherical surfaces.

The optical data of this preferred embodiment are listed in Table 10,wherein the object-side surface and the image-side surface of the firstlens element 410 to the sixth lens element 460 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 11 as follows:

TABLE 11 Aspheric coefficients of this preferred embodiment Surface # 12 4 5 6 7 k = −5.56244E+00 −1.00000E+00 −1.00000E+00 −1.00000E+00−1.00000E+00 −2.00000E+01 A4 = 2.47866E−01 −1.71073E−02 8.07736E−031.49833E−02 −2.89736E−01 −1.85178E−01 A6 = −2.08873E−01 5.08254E−023.15479E−02 6.37134E−02 −1.25664E−01 −5.07734E−02 A8 = 2.34631E−01−1.78675E−01 3.11035E−01 1.15615E−01 3.38802E−01 7.28808E−02 A10 =−1.94352E−01 4.02793E−01 −9.86554E−01 −3.31940E−01 −5.96517E−01−8.45399E−02 A12 = 7.27048E−02 −5.62451E−01 1.41570E+00 4.54146E−013.51936E−01 4.94729E−02 A14 = −2.80062E−02 3.18694E−01 −6.99918E−01−1.14217E−01 Surface # 8 9 10 11 12 13 k = 3.92655E+00 9.50269E−02−1.00000E+01 −7.06168E+01 −1.00000E+00 −1.08280E−01 A4 = 9.30871E−02−2.29546E−02 −7.81893E−02 −1.35949E−01 −4.60189E−02 −9.53831E−02 A6 =4.84084E−03 1.69538E−02 −1.11802E−02 1.35294E−01 −1.93407E−022.10887E−02 A8 = −2.15180E−01 1.30017E−02 −1.06410E−02 −1.37421E−011.24675E−02 −6.20149E−03 A10 = 3.16061E−01 −4.11645E−04 6.21482E−036.85949E−02 −1.01039E−03 1.51834E−03 A12 = −1.76301E−01 −1.46444E−02−1.53119E−04 −2.39953E−04 A14 = 3.99882E−02 1.07415E−03 1.50385E−051.58284E−05

With reference to Table 10 and FIG. 4B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=4.22 (mm), an f-number Fno=2.80, and a halfof maximum view angle HFOV=33.5°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 12below, and the related symbols have been described above and thus willnot be described again.

TABLE 12 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 35.4 f/f₁ 1.51 (CT₃ + CT₄ + CT₅)/f 0.27|f/f₅| + |f/f₆| 2.11 T₁₂/T₂₃ 0.15 Y_(C)/f 0.24 R₁₂/f 0.85 S_(D)/T_(D)0.85 (R₃ + R₄)/(R₃ − R₄) 0.73 TTL [mm] 4.74 (R₇ − R₈)/(R₇ + R₈) 0.18TTL/ImgH 1.65 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) −0.07

According to the optical data as shown in Table 10 and the series ofaberration curves as shown in FIG. 4B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

Fifth Preferred Embodiment

With reference to FIGS. 5A and 5B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the fifth preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 570. More specifically, the stop canbe an aperture stop 500, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: an aperture stop 500, the plastic first lenselement 510 with positive refractive power having a convex object-sidesurface 511, and a convex image-side surface 512, and both object-sidesurface 511 and image-side surface 512 being aspheric; the plasticsecond lens element 520 with negative refractive power having a concaveobject-side surface 521 and a concave image-side surface 522, bothobject-side surface 521 and image-side surface 522 being aspheric; theplastic third lens element 530 with positive refractive power having aconvex object-side surface 531 and a convex image-side surface 532, andboth object-side surface 531 and image-side surface 532 being aspheric;the plastic fourth lens element 540 with positive refractive powerhaving a concave object-side surface 541, and a convex image-sidesurface 542, and both object-side surface 541 and image-side surface 542being aspheric; the plastic fifth lens element 550 with positiverefractive power having a convex object-side surface 551 and a conveximage-side surface 552, and both object-side surface 551 and image-sidesurface 552 being aspheric; the plastic sixth lens element 560 withnegative refractive power having a concave object-side surface 561 and aconcave image-side surface 562, and both object-side surface 561 andimage-side surface 562 being aspheric, and the image-side surface 562having at least one inflection point; an IR-filter 570 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 590 at an image plane 580. With thecombination of the six lens elements, the aperture stop 500 and theIR-filter 570, an image of the object to be photographed can be formedat the image sensor 590.

TABLE 13 Optical data of this preferred embodiment f = 4.80 mm, Fno =2.80, HFOV = 30.5 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Ape. Stop Plano−0.100   2 Lens 1   2.403880 0.848 Plastic 1.514 56.8 2.92 (ASP) 3  −3.497700 0.110 (ASP) 4 Lens 2 −2787.211900 0.436 Plastic 1.607 26.6−4.01 (ASP) 5   2.438760 0.394 (ASP) 6 Lens 3  304.487300 0.307 Plastic1.614 25.6 72.38 (ASP) 7  −52.037200 0.605 (ASP) 8 Lens 4   −3.0012000.563 Plastic 1.530 55.8 31.21 (ASP) 9   −2.705390 0.070 (ASP) 10 Lens 5  2.131960 0.466 Plastic 1.530 55.8 3.70 (ASP) 11  −22.727300 0.270(ASP) 12 Lens 6  −11.231800 0.420 Plastic 1.530 55.8 −2.66 (ASP) 13  1.632380 0.700 (ASP) 14 IR-filter Plano 0.400 Glass 1.517 64.2 — 15Plano 0.303 16 Image Plano — Note: Reference wavelength is 587.6 nm. ASPstands for aspherical surfaces.

The optical data of this preferred embodiment are listed in Table 13,wherein the object-side surface and the image-side surface of the firstlens element 510 to the sixth lens element 560 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 14 as follows:

TABLE 14 Aspheric coefficients of this preferred embodiment Surface # 23 4 5 6 7 k = −9.33720E−01 −1.56254E+01 6.10000E+01 −2.56256E+00−9.20000E+01 −1.00000E+00 A4 = −8.06175E−03 −3.50729E−02 −1.34569E−02−3.32568E−03 −2.67191E−03 1.18409E−02 A6 = −1.22665E−02 −4.88209E−02−4.37759E−02 2.69532E−03 6.28878E−03 −4.05675E−02 A8 = −3.53590E−036.95046E−03 −8.40070E−03 −1.33094E−02 2.62007E−03 3.72133E−02 A10 =−1.41650E−02 −2.46406E−04 2.88941E−02 6.31942E−03 −1.07863E−03−1.69236E−02 A12 = −3.56386E−03 5.05519E−03 Surface # 8 9 10 11 12 13 k= −4.79946E+01 8.70768E−01 −1.48994E+01 −1.00000E+00 −4.70000E+01−5.88041E+00 A4 = 1.53327E−02 −1.32637E−02 −6.73656E−02 −3.79305E−04−5.81894E−03 −2.87431E−02 A6 = −4.63194E−02 1.51928E−02 1.93738E−023.96015E−03 2.24230E−03 4.19953E−03 A8 = 1.47455E−02 −5.33053E−03−6.76759E−04 −1.83527E−03 −7.73374E−05 −2.97559E−04 A10 = −6.50598E−03−4.42414E−04 −9.49684E−04 1.70888E−04 −8.49537E−06 −3.80301E−06 A12 =−6.78558E−05 1.47507E−04 1.24320E−04 3.33773E−06 −3.51282E−072.04502E−06 A14 = 3.22460E−06 −2.17803E−08 −1.09259E−07

With reference to Table 13 and FIG. 5B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=4.80 (mm), an f-number Fno=2.80, and a halfof maximum view angle HFOV=30.5°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 15, andthe related symbols have been described above and thus will not bedescribed again.

TABLE 15 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 30.2 f/f₁ 1.65 (CT₃ + CT₄ + CT₅)/f 0.28|f/f₅| + |f/f₆| 3.10 T₁₂/T₂₃ 0.28 Y_(C)/f 0.43 R₁₂/f 0.34 S_(D)/T_(D)0.98 (R₃ + R₄)/(R₃ − R₄) 1.00 TTL [mm] 5.76 (R₇ − R₈)/(R₇ + R₈) 0.05TTL/ImgH 2.02 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) 0.75

According to the optical data as shown in Table 13 and the series ofaberration curves as shown in FIG. 5B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

Sixth Preferred Embodiment

With reference to FIGS. 6A and 6B for a schematic view and a series ofaberration curves of an optical imaging system for pickup in accordancewith the sixth preferred embodiment of the present inventionrespectively, the optical imaging system for pickup comprises six lenselements, a stop and an IR-filter 670. More specifically, the stop canbe an aperture stop 600, and the optical imaging system for pickup,sequentially arranged from an object side to an image side along anoptical axis, comprises: an aperture stop 600; the plastic first lenselement 610 with positive refractive power having a convex object-sidesurface 611, and a convex image-side surface 612, and both object-sidesurface 611 and image-side surface 612 being aspheric; the plasticsecond lens element 620 with negative refractive power having a concaveobject-side surface 621 and a concave image-side surface 622, bothobject-side surface 621 and image-side surface 622 being aspheric; theplastic third lens element 630 with positive refractive power having aconcave object-side surface 631 and a convex image-side surface 632, andboth object-side surface 631 and image-side surface 632 being aspheric;the plastic fourth lens element 640 with positive refractive powerhaving a concave object-side surface 641, and a convex image-sidesurface 642, and both object-side surface 641 and image-side surface 642being aspheric; the plastic fifth lens element 650 with negativerefractive power having a convex object-side surface 651 and a concaveimage-side surface 652, and both object-side surface 651 and image-sidesurface 652 being aspheric; the plastic sixth lens element 660 withnegative refractive power having a concave object-side surface 661 and aconcave image-side surface 662, and both object-side surface 661 andimage-side surface 662 being aspheric, and the image-side surface 662having at least one inflection point; an IR-filter 670 made of panelglass for adjusting a wavelength section of the imaging light that canpass through, and an image sensor 690 at an image plane 680. With thecombination of the six lens elements, the aperture stop 600 and theIR-filter 670, an image of the photographed object to can be formed atthe image sensor 690.

TABLE 16 Optical data of this preferred embodiment f = 5.23 mm, Fno =3.20, HFOV = 33.3 deg. Focal Surface # Curvature Radius ThicknessMaterial Index Abbe # length 0 Object Plano Infinity 1 Ape. Stop Plano−0.133   2 Lens 1  2.127090 (ASP) 0.740 Plastic 1.543 56.5 2.77 3 −4.512500 (ASP) 0.050 4 Lens 2 −33.100400 (ASP) 0.337 Plastic 1.60726.6 −4.52 5  3.003100 (ASP) 0.669 6 Lens 3  −2.741420 (ASP) 0.550Plastic 1.583 30.2 8.49 7  −1.894860 (ASP) 0.177 8 Lens 4  −1.947400(ASP) 0.644 Plastic 1.543 56.5 5.74 9  −1.338350 (ASP) 0.088 10 Lens 5 2.412200 (ASP) 0.348 Plastic 1.633 23.4 −4.59 11  1.244550 (ASP) 0.71712 Lens 6 −21.654700 (ASP) 0.842 Plastic 1.633 23.4 −6.21 13  4.869300(ASP) 0.500 14 IR-filter Plano 0.300 Glass 1.517 64.2 — 15 Plano 0.22316 Image Plano — Note: Reference wavelength is 587.6 nm. ASP stands foraspherical surfaces.

The optical data of this preferred embodiment are listed in Table 16,wherein the object-side surface and the image-side surface of the firstlens element 610 to the sixth lens element 660 comply with the asphericsurface formula as given in Equation (15), and their asphericcoefficients are listed in Table 17 as follows:

TABLE 17 Aspheric coefficients of this preferred embodiment Surface # 23 4 5 6 7 k = −5.20024E−01 −4.17568E+01 9.64829E+00 −1.29601E+01−4.38345E+00 8.87301E−01 A4 = −2.28820E−03 −4.34779E−02 4.16326E−035.19024E−02 −6.71647E−02 −5.34952E−03 A6 = −2.03356E−02 −3.34775E−02−2.91330E−02 3.93263E−04 −8.41760E−03 3.57259E−04 A8 = 1.74682E−021.09461E−02 1.45443E−02 3.30179E−03 1.10480E−03 2.15456E−03 A10 =−3.74325E−02 −2.15462E−02 −1.42353E−03 6.14962E−03 7.39043E−041.49800E−03 A12 = −2.34374E−03 −9.54292E−04 −1.50006E−03 2.67525E−04Surface # 8 9 10 11 12 13 k = 8.26271E−01 −2.40901E+00 −1.22871E+01−4.09513E+00 −1.00000E+00 −7.55740E+01 A4 = −7.76505E−04 −2.44078E−02−5.29855E−02 −3.63895E−02 5.40063E−03 −2.48920E−02 A6 = 1.38964E−03−1.92131E−03 3.04904E−03 6.11537E−03 1.85690E−04 2.84633E−03 A8 =1.05688E−03 −1.65014E−04 2.85766E−04 −5.22029E−04 −5.47682E−05−1.92311E−05 A10 = 9.90431E−04 4.45575E−04 −6.27859E−05 1.14436E−052.42222E−07 −1.27509E−05 A12 = 4.18688E−05 1.50221E−05 1.32732E−062.71179E−09 1.45397E−07 A14 = −1.13613E−08 3.15645E−09 −2.64304E−098.21323E−09 A16 = −1.02245E−08 −5.22326E−10 2.84532E−11 6.04089E−11

With reference to Table 16 and FIG. 6B for an optical imaging system forpickup of this preferred embodiment, the optical imaging system forpickup has a focal length f=5.23 (mm), an f-number Fno=3.20, and a halfof maximum view angle HFOV=33.3°. After the optical data of thispreferred embodiment are calculated and derived, the optical imagingsystem for pickup satisfies related conditions as shown in Table 18, andthe related symbols have been described above and thus will not bedescribed again.

TABLE 18 Data of related relations of this preferred embodiment RelationData Relation Data v₁ − v₂ 29.9 f/f₁ 1.89 (CT₃ + CT₄ + CT₅)/f 0.30|f/f₅| + |f/f₆| 1.98 T₁₂/T₂₃ 0.07 Y_(C)/f 0.21 R₁₂/f 0.93 S_(D)/T_(D)0.97 (R₃ + R₄)/(R₃ − R₄) 0.83 TTL [mm] 6.08 (R₇ − R₈)/(R₇ + R₈) 0.19TTL/ImgH 1.72 (R₁₁ + R₁₂)/(R₁₁ − R₁₂) 0.63

According to the optical data as shown in Table 16 and the series ofaberration curves as shown in FIG. 6B, the optical imaging system forpickup in accordance with this preferred embodiment of the presentinvention provides good correction results in aspects of thelongitudinal spherical aberration, astigmatic field curving, anddistortion.

In the optical imaging system for pickup of the present invention, ifthe lens element has a convex surface, then the surface of the lenselement is convex at a paraxial position; and if the lens element has aconcave surface, then the surface of the lens element is concave at aparaxial position.

In the optical imaging system for pickup of the present invention, atleast one stop such as a glare stop or a field stop can be provided forreducing stray lights to improve the image quality, limiting the fieldsize, or other functionalities. At least one stop can be positionedbefore the first lens element, between lens elements, or before theimage plane within the optical imaging system for pickup depending onthe preference of the optical designer. Additionally, the opticalimaging system for pickup can also be utilized in 3D (three-dimensional)applications.

Tables 1 to 18 show changes of values of an optical imaging lensassembly in accordance with different preferred embodiments of thepresent invention respectively, and even if different values are used,products of the same structure are intended to be covered by the scopeof the present invention. It is noteworthy to point out that theaforementioned description and the illustration of related drawings areprovided for the purpose of explaining the technical characteristics ofthe present invention, but not intended for limiting the scope of thepresent invention.

1. An optical imaging system for pickup, sequentially arranged from anobject side to an image side comprising: a first lens element withpositive refractive power, having a convex object-side surface; a secondlens element with refractive power; a third lens element with refractivepower; a fourth lens element with refractive power; a fifth lens elementwith refractive power; and a plastic sixth lens element with refractivepower having a concave image-side surface, both object-side surface andimage-side surface being aspheric, and the image-side surface having atleast one inflection point; wherein f is a focal length of the opticalimaging system for pickup, f₅ is a focal length of the fifth lenselement, f₆ is a focal length of the sixth lens element, and thefollowing relation is satisfied:1.8<|f/f ₅ |+|f/f ⁶|<3.5.
 2. The optical imaging system for pickup ofclaim 1, wherein the sixth lens element has negative refractive power.3. The optical imaging system for pickup of claim 2, wherein the secondlens element has negative refractive power.
 4. The optical imagingsystem for pickup of claim 3, wherein the fifth lens element haspositive refractive power.
 5. The optical imaging system for pickup ofclaim 4, further comprising a stop, wherein T_(D) is an axial distancebetween the object-side surface of the first lens element and theimage-side surface of the sixth lens element, S_(D) is an axial distancebetween the stop and the image-side surface of the sixth lens element,and the following relation is satisfied:0.7<S _(D) /T _(D)<1.2.
 6. The optical imaging system for pickup ofclaim 5, wherein f is the focal length of the optical imaging system forpickup, CT₃ is a central thickness of the third lens element, CT₄ is acentral thickness of the fourth lens element, CT₅ is a central thicknessof the fifth lens element, and the following relation is satisfied:0.2<(CT ₃ +CT ₄ +CT ₅)/f<0.4.
 7. The optical imaging system for pickupof claim 5, wherein the optical imaging system for pickup comprises atleast three plastic lens elements and further comprises an image sensorat an image plane for imaging an photographed object; TTL is an axialdistance between the object-side surface of the first lens element andthe image plane, ImgH is half of an diagonal length of an effectivephotosensitive area of the image sensor, and the following relation issatisfied:TTL/ImgH<2.1.
 8. The optical imaging system for pickup of claim 5,wherein R₇ is a curvature radius of the object-side surface of thefourth lens element, R₈ is a curvature radius of the image-side surfaceof the fourth lens element, and the following relation is satisfied:0<(R ₂ −R ₈)/(R ₂ +R ₈)<0.6.
 9. The optical imaging system for pickup ofclaim 5, wherein R₃ is a curvature radius of the object-side surface ofthe second lens element, R₄ is a curvature radius of the image-sidesurface of the second lens element, and the following relation issatisfied:0<(R ₃ +R ₄)/(R ₃ −R ₄)<1.5.
 10. The optical imaging system for pickupof claim 5, wherein the second lens element has a concave image-sidesurface, the sixth lens element has a concave object-side surface, f isthe focal length of the optical imaging system for pickup, f₅ is thefocal length of the fifth lens element, f₆ is the focal length of thesixth lens element, and the following relation is satisfied:2.0<|f/f ₅ |+|f/f ₆|<3.2.
 11. The optical imaging system for pickup ofclaim 3, wherein f is the focal length of the optical imaging system forpickup, f₁ is a focal length of the first lens element, and thefollowing relation is satisfied:1.0<f/f ₁<2.0.
 12. The optical imaging system for pickup of claim 11,wherein v₁ is an Abbe number of the first lens element, v₂ is an Abbenumber of the second lens element, and the following relation issatisfied:25<v ₁-v ₂<40.
 13. The optical imaging system for pickup of claim 12,wherein the second lens element has a concave image-side surface; thefourth lens element has a concave object-side surface and a conveximage-side surface; the fifth lens element has a concave object-sidesurface and a convex image-side surface; the sixth lens element has aconcave object-side surface.
 14. The optical imaging system for pickupof claim 12, wherein R₁₁ is a curvature radius of the object-sidesurface of the sixth lens element, R₁₂ is a curvature radius of theimage-side surface of the sixth lens element, and the following relationis satisfied:−0.2<(R ₁₁ +R ₁₂)/(R ₁₁ −R ₁₂)<0.9.
 15. The optical imaging system forpickup of claim 12, further comprising an image plane, wherein TTL is anaxial distance between the object-side surface of the first lens elementand the image plane, and the following relation is satisfied:3.7 mm<TTL<6.5 mm.
 16. The optical imaging system for pickup of claim 4,wherein Y_(C) is a vertical distance between the outermost horizontalvertex of the image side surface of the sixth lens element and theoptical axis, and f is the focal length of the optical imaging systemfor pickup, and the following relation is satisfied:0.1<Y _(C) /f<0.8.
 17. The optical imaging system for pickup of claim16, wherein R₁₂ is a curvature radius of the image-side surface of thesixth lens element, f is the focal length of the optical imaging systemfor pickup, and the following relation is satisfied:0.2<R ₁₂ /f<1.2.
 18. The optical imaging system for pickup of claim 16,wherein the second lens element has a concave image-side surface, andthe sixth lens element has a concave object-side surface.
 19. Theoptical imaging system for pickup of claim 16, wherein T₁₂ is an axialdistance between the first lens element and the second lens element, T₂₃is an axial distance between the second lens element and the third lenselement, and the following relation is satisfied:0.03<T ₁₂ /T ₂₃<0.3.
 20. The optical imaging system for pickup of claim2, further comprising an image sensor at an image plane for imaging anphotographed object; wherein TTL is an axial distance between theobject-side surface of the first lens element and the image plane, ImgHis half of an diagonal length of an effective photosensitive area of theimage sensor, and the following relation is satisfied:TTL/ImgH<2.1.
 21. An optical imaging system for pickup, sequentiallyarranged from an object side to an image side comprising: a first lenselement with positive refractive power, having a convex object-sidesurface; a second lens element with refractive power; a third lenselement with refractive power; a fourth lens element with refractivepower; a fifth lens element with refractive power; and a plastic sixthlens element with refractive power having a concave image-side surface,both object-side surface and image-side surface thereof being aspheric,and the image-side surface having at least one inflection point; whereinf is a focal length of the optical imaging system for pickup, f₅ is afocal length of the fifth lens element, f₆ is a focal length of thesixth lens element, and Y_(C) is a vertical distance between theoutermost horizontal vertex of the image side surface of the sixth lenselement and the optical axis, and the following relations are satisfied:1.8<|f/f ₅ |+|f/f ₆|<3.5; and0.1<Y _(C) /f<0.8.
 22. The optical imaging system for pickup of claim21, further comprising an image plane, wherein TTL is an axial distancebetween the object-side surface of the first lens element and the imageplane, and the following relation is satisfied:3.7 mm<TTL<6.5 mm.
 23. The optical imaging system for pickup of claim21, wherein the second lens element has a concave image-side surface;the fourth lens element has a concave object-side surface and a conveximage-side surface; the fifth lens element has a concave object-sidesurface and a convex image-side surface; and the sixth lens element hasa concave object-side surface.